The present invention relates to a sheet feeder and in particular to a sheet feeder having single sheet bypass capability with, for example, a sheet of a different stock from the stock present in the feed tray of the regular sheet feeder. More particularly, it's directed to such a sheet feeder for use in automatic printing machines.
In automatic printing machines there typically is at least one if not several sheet supply trays which may take the form of a fixed tray or a cassette having sheets of different sizes or weights. During operation, the sheet is fed from the single tray or fed from a tray selected on the control console of the automatic printing machine. In the routine use of such automatic printing devices, it frequently happens that the user wishes to make a print on sheet stock which is other than that in the single or plurality of sheet supplied trays. This of course may be accomplished by changing the supply of sheets in any one of the sheet supply trays in the automatic printing machine. However, to change such supply when only a small number or even one sheet of a different stock is desired is time consuming and inefficient.
Previous approaches to solving this problem have either used a cover which was placed over a print sheet supply tray or a separate tray that was pushed over the print sheet supply tray in the machine underneath the feed wheels to feed a single sheet from the separate tray on top of the stack. Alternatively, other geometries used a separate set of feed wheels to feed the bypass sheet into the sheet path.